NOAO >   Observing Info >   Approved Programs >   2011A-0088

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Proposal Information for 2011A-0088


PI: Mukremin Kilic, Smithsonian Astrophysical Observatory, mkilic@cfa.harvard.edu
Address: 60 Garden Street, Cambridge, MA 02138, USA

CoI: Patrick Dufour, University of Montreal

Title: The Chemical Composition of an Extrasolar Dwarf Planet

Abstract: We recently discovered the most metal-rich white dwarf currently known. Our follow-up MMT spectroscopy shows that SDSS J0738+1835 has a helium dominated atmosphere polluted with significant amounts of O, Mg, Si, Ca, and Fe. J0738+1835 is 10 \times more metal-rich than any other known white dwarf and it is even more metal-rich than the Sun. The large amounts of oxygen present in the photosphere of this star indicates that the accreted object was similar to Earth. J0738+1835 has an amount of metals similar to the mass of the dwarf planet Ceres. We also detect the tidally disrupted remains of this extrasolar body in the form of a circumstellar debris disk. We propose to obtain Keck high- resolution spectroscopy of J0738+1835 to study the atmospheric composition of this star, and therefore the composition of the accreted dwarf planet, accurately. No other currently available technique can observe the bulk composition of extrasolar material - this is the singular, enormous advantage offered by this unique white dwarf.


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NOAO >   Observing Info >   Approved Programs >   2011A-0088

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